Arduino outputting wrong variables

Projects Programming
1

Hello.

The code I'm running is a simple read the adc and return the value over UART.
I'm currently experimenting with averaging the adc value.
And I'm constantly checking that i have a proper samplerate, by incrementing the variable for every read.

However when i print it out it returns what ever i have set the ampraw variable to +1.

So could you take a look at my code to see if I'm doing anything wrong.

I've tried it on a few Arduino WAN1300's
that's the one i'm running the code on.

Thanks.

int tid=millis();
int ampraw=0;
int amprawhigh=0;
int amprawlow=4096;
//int samples=0;
int avg=0;
const int avgsamplecount=3;
int avgsamples[3];
int samplerate=0;


// the setup routine runs once when you press reset:
void setup() {
  // initialize serial communication at 9600 bits per second:
  
  Serial.begin(115000);


  analogReference(AR_INTERNAL1V0);
  analogReadResolution(12);
  delay(1000);
  amprawlow=4096;
  amprawhigh=0;
  tid=millis(); 
  while ((millis()-tid)<10000) {
    //here i'm fixing the the ADC data so I can isolate the problem
    ampraw =  2; //analogRead(A0);
    if (ampraw<amprawlow) {
      amprawlow=ampraw;
    }
    if (ampraw>amprawhigh) {
      amprawhigh=ampraw;
    }
    for (int i=0;i<avgsamplecount;i++) {
      avgsamples[i]=avgsamples[i+1];
    }
    avgsamples[avgsamplecount]=ampraw;
    avg=0;
    for (int i=0;i<=avgsamplecount;i++) {
      avg=avg+avgsamples[i];
    }

    samplerate++;
    delayMicroseconds(100);
    //For somereason when i print the samplerate variable it returns the ampraw value +1.
    //I know this because if i change it the serial output changes.
    
    
    Serial.println(samplerate);
  }
 Serial.println(samplerate);

  
  

}

// the loop routine runs over and over again forever:
void loop() {

  
}
2

Check your accessed index in the array.

You are accessing elements that are not in your array.

3

Your code

    for (int i=0;i<avgsamplecount;i++) {
      avgsamples[i]=avgsamples[i+1];
    }

When i equals 2, your reading element with index 3 that does not belong to the array.

Your code

avgsamples[avgsamplecount]=ampraw;

You're writing the element with index 3 which which is not an element of the array. Undefined behaviour can be the result.

Not said that fixing those will fix your problem.

4

Ah yes. Ofcourse.

Thank you so much for you help.